HTTP/1.1 405 Method Not Allowed...

Situation: a client application (W2K) connect to web server (Aix). The
client has the ability to backup or restore register settings (with a file
xxx.xxx.xxx.reg). The method used is via "http" port 80.

Problem: every time the client attempts to backup/restore registry, the
error returned is "HTTP/1.1 405 Method Not Allowed"

Note: the HTTP server works as I am able to display server URL's from IE.

Does anyone have an idea what the problem could be? Anything to do with my
Web server config?